The United States Fish and Wildlife Service says the development of two-thirds of Tinian land in the Northern Marianas for defence purposes will harm the habitat of already threatened plant species.
The service says one rare plant species in particular, the Heritiera longipetiolata, is found on land leased to the US Defence Department.
The US military could have a stake in the proposed listing of 23 Marianas plant and animal species under the Endangered Species Act.
Fish and Wildlife says live fire training on the island would also harm the species.